public class Car3 {
    int seat;
    String displacement;
    public Car3(){

    }
    public Car3(int seat,String displacement){
        this.seat=seat;
        this.displacement=displacement;
    }
    public String start(){
        return "汽车启动了，开的很快";
    }
    public String brake(){
        return "汽车遇到红灯，缓慢刹车";
    }
}
